Re: [RFC v3 04/11] vhost-vdpa: protect concurrent access to vhost device iotlb

[Jason Wang]

On 2021/1/19 下午12:59, Xie Yongji wrote:

Introduce a mutex to protect vhost device iotlb from
concurrent access.

Fixes: 4c8cf318("vhost: introduce vDPA-based backend")
Signed-off-by: Xie Yongji <xieyon...@bytedance.com>
---
  drivers/vhost/vdpa.c | 4 ++++
  1 file changed, 4 insertions(+)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 448be7875b6d..4a241d380c40 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -49,6 +49,7 @@ struct vhost_vdpa {
        struct eventfd_ctx *config_ctx;
        int in_batch;
        struct vdpa_iova_range range;
+       struct mutex mutex;

Let's use the device mutex like what vhost_process_iotlb_msg() did.

Thanks

  };

static DEFINE_IDA(vhost_vdpa_ida);

@@ -728,6 +729,7 @@ static int vhost_vdpa_process_iotlb_msg(struct vhost_dev 
*dev,
        if (r)
                return r;

+ mutex_lock(&v->mutex);

        switch (msg->type) {
        case VHOST_IOTLB_UPDATE:
                r = vhost_vdpa_process_iotlb_update(v, msg);
@@ -747,6 +749,7 @@ static int vhost_vdpa_process_iotlb_msg(struct vhost_dev 
*dev,
                r = -EINVAL;
                break;
        }
+       mutex_unlock(&v->mutex);

return r;

  }
@@ -1017,6 +1020,7 @@ static int vhost_vdpa_probe(struct vdpa_device *vdpa)
                return minor;
        }

+ mutex_init(&v->mutex);

        atomic_set(&v->opened, 0);
        v->minor = minor;
        v->vdpa = vdpa;